PHP的PDO常用类库实例分析

<?php
// 连接数据库
class db {
  static public function getdb() {
    try {
      $pdo = new pdo(db_dsn, db_user, db_pwd);
      $pdo->setattribute(pdo::attr_persistent, true); // 设置数据库连接为持久连接
      $pdo->setattribute(pdo::attr_errmode, pdo::errmode_exception); // 设置抛出错误
      $pdo->setattribute(pdo::attr_oracle_nulls, true); // 设置当字符串为空转换为 sql 的 null
      $pdo->query('set names utf8'); // 设置数据库编码
    } catch (pdoexception $e) {
      exit('数据库连接错误，错误信息：'. $e->getmessage());
    }
    return $pdo;
  }
}
?>

<?php
/**
* 数据库操作类库
* author lee.
* last modify $date: 2012-1-19 13:59；04 $
*/
class m {
  private $_db; //数据库句柄
  public $_sql; //sql语句
  /**
   * 构造方法
   */
  public function __construct() {
    $this->_db = db::getdb();
  }
  /**
   * 数据库添加操作
   * @param string $tname 表名
   * @param array $field 字段数组
   * @param array $val 值数组
   * @param bool $is_lastinsertid 是否返回添加id
   * @return int 默认返回成功与否，$is_lastinsertid 为true，返回添加id
   */
  public function insert($tname, $fields, $vals, $is_lastinsertid=false) {
    try {
      if (!is_array($fields) || !is_array($vals))
        exit($this->geterror(__function__, __line__));
      $fields = $this->formatarr($fields);
      $vals = $this->formatarr($vals, false);
      $tname = $this->formattabname($tname);
      $this->_sql = "insert into {$tname} ({$fields}) values ({$vals})";
      if (!$is_lastinsertid) {
        $row = $this->_db->exec($this->_sql);
        return $row;
      } else {
        $this->_db->exec($this->_sql);
        $lastid = (int)$this->_db->lastinsertid();
        return $lastid;
      }
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 数据库修改操作
   * @param string $tname 表名
   * @param array $field 字段数组
   * @param array $val 值数组
   * @param string $condition 条件
   * @return int 受影响的行数
   */
  public function update($tname, $fieldval, $condition) {
    try {
      if (!is_array($fieldval) || !is_string($tname) || !is_string($condition))
        exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $upstr = '';
      foreach ($fieldval as $k=>$v) {
        $upstr .= '`'.$k . '`=' . '\'' . $v . '\'' . ',';
      }
      $upstr = rtrim($upstr, ',');
      $this->_sql = "update {$tname} set {$upstr} where {$condition}";
      $row = $this->_db->exec($this->_sql);
      return $row;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 数据库删除操作（注：必须添加 where 条件）
   * @param string $tname 表名
   * @param string $condition 条件
   * @return int 受影响的行数
   */
  public function del($tname, $condition) {
    try {
      if (!is_string($tname) || !is_string($condition))
        exit($this->geterror(__function__, __line__));
      $tname= $this->formattabname($tname);
      $this->_sql = "delete from {$tname} where {$condition}";
      $row = $this->_db->exec($this->_sql);
      return $row;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 返回表总个数
   * @param string $tname 表名
   * @param string $condition 条件
   * @return int
   */
  public function total($tname, $condition='') {
    try {
      if (!is_string($tname))
        exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $this->_sql = "select count(*) as total from {$tname}" .
      ($condition=='' ? '' : ' where ' . $condition);
      $re = $this->_db->query($this->_sql);
      foreach ($re as $v) {
        $total = $v['total'];
      }
      return (int)$total;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 数据库删除多条数据
   * @param string $tname 表名
   * @param string $field 依赖字段
   * @param array $ids 删除数组
   * @return int 受影响的行数
   */
  public function delmulti($tname, $field, $ids) {
    try {
      if (!is_string($tname) || !is_array($ids))
        exit($this->geterror(__function__, __line__));
      $delstr = '';
      $tname = $this->formattabname($tname);
      $field = $this->formattabname($field);
      foreach ($ids as $v) {
        $delstr .= $v . ',';
      }
      $delstr = rtrim($delstr, ',');
      $this->_sql = "delete from {$tname} where {$field} in ({$delstr})";
      $row = $this->_db->exec($this->_sql);
      return $row;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 获取表格的最后主键（注：针对 int 类型）
   * @param string $tname 表名
   * @return int
   */
  public function insertid($tname) {
    try {
      if (!is_string($tname))
        exit($this->geterror(__function__, __line__));
      $this->_sql = "show table status like '{$tname}'";
      $result = $this->_db->query($this->_sql);
      $insert_id = 0;
      foreach ($result as $v) {
        $insert_id = $v['auto_increment'];
      }
      return (int)$insert_id;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 检查数据是否已经存在（依赖条件）
   * @param string $tname 表名
   * @param string $field 依赖的字段
   * @return bool
   */
  public function exists($tname, $condition) {
    try {
      if (!is_string($tname) || !is_string($condition))
        exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $this->_sql = "select count(*) as total from {$tname} where {$condition}";
      $result = $this->_db->query($this->_sql);
      foreach ($result as $v) {
         $b = $v['total'];
      }
      if ($b) {
        return true;
      } else {
        return false;
      }
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 检查数据是否已经存在（依赖 int 主键）
   * @param string $tname 表名
   * @param string $primary 主键
   * @param int $id 主键值
   * @return bool
   */
  public function existsbypk($tname, $primary, $id) {
    try {
      if (!is_string($tname) || !is_string($primary)
      || !is_int($id))
        exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $this->_sql = "select count(*) as total from {$tname} where {$primary} = ". $id;
      $result = $this->_db->query($this->_sql);
      foreach ($result as $v) {
         $b = $v['total'];
      }
      if ($b) {
        return true;
      } else {
        return false;
      }
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 预处理删除（注：针对主键为 int 类型，推荐使用）
   * @param string $tname 表名
   * @param string $primary 主键字段
   * @param int or array or string $ids 如果是删除一条为 int，多条为 array，删除一个范围为 string
   * @return int 返回受影响的行数
   */
  public function delbypk($tname, $primary, $ids, $mult=false) {
    try {
      if (!is_string($tname) || !is_string($primary)
      || (!is_int($ids) && !is_array($ids) && !is_string($ids))
      || !is_bool($mult)) exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $stmt = $this->_db->prepare("delete from {$tname} where {$primary}=?");
      if (!$mult) {
        $stmt->bindparam(1, $ids);
        $row = $stmt->execute();
      } else {
        if (is_array($ids)) {
          $row = 0;
          foreach ($ids as $v) {
            $stmt->bindparam(1, $v);
            if ($stmt->execute()) {
              $row++;
            }
          }
        } elseif (is_string($ids)) {
          if (!strpos($ids, '-'))
            exit($this->geterror(__function__, __line__));
          $split = explode('-', $ids);
          if (count($split)!=2 || $split[0]>$split[1])
            exit($this->geterror(__function__, __line__));
          $i = null;
          $count = $split[1]-$split[0]+1;
          for ($i=0; $i<$count; $i++) {
            $idarr[$i] = $split[0]++;
          }
          $idstr = '';
          foreach ($idarr as $id) {
            $idstr .= $id . ',';
          }
          $idstr = rtrim($idstr, ',');
          $this->_sql ="delete from {$tname} where {$primary} in ({$idstr})";
          $row = $this->_db->exec($this->_sql);
        }
      }
      return $row;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 返回单个字段数据或单条记录
   * @param string $tname 表名
   * @param string $condition 条件
   * @param string or array $fields 返回的字段，默认是*
   * @return string || array
   */
  public function getrow($tname, $condition='', $fields="*") {
    try {
      if (!is_string($tname) || !is_string($condition)
      || !is_string($fields) || empty($fields))
         exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $this->_sql = "select {$fields} from {$tname} ";
      $this->_sql .= ($condition=='' ? '' : "where {$condition}") . " limit 1";
      $sth = $this->_db->prepare($this->_sql);
      $sth->execute();
      $result = $sth->fetch(pdo::fetch_assoc);
      if ($fields === '*') {
        return $result;
      } else {
        return $result[$fields];
      }
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 返回多条数据
   * @param string $tname 表名
   * @param string $fields 返回字段，默认为*
   * @param string $condition 条件
   * @param string $order 排序
   * @param string $limit 显示个数
   * @return pdostatement
   */
  public function getall($tname, $fields='*', $condition='', $order='', $limit='') {
    try {
      if (!is_string($tname) || !is_string($fields)
      || !is_string($condition) || !is_string($order)
      || !is_string($limit))
        exit($this->geterror(__function__, __line__));
      $tname = $this->formattabname($tname);
      $fields = ($fields=='*' || $fields=='') ? '*' : $fields;
      $condition = $condition=='' ? '' : " where ". $condition ;
      $order = $order=='' ? '' : " order by ". $order;
      $limit = $limit=='' ? '' : " limit ". $limit;
      $this->_sql = "select {$fields} from {$tname} {$condition} {$order} {$limit}";
      $sth = $this->_db->prepare($this->_sql);
      $sth->execute();
      $result = $sth->fetchall(pdo::fetch_assoc);
      return $result;
    } catch (pdoexception $e) {
      exit($e->getmessage());
    }
  }
  /**
   * 格式化数组（表结构和值）
   * @param array $field
   * @param bool $isfield
   * @return string
   */
  private function formatarr($field, $isfield=true) {
    if (!is_array($field)) exit($this->geterror(__function__, __line__));
    $fields = '';
    if ($isfield) {
      foreach ($field as $v) {
        $fields .= '`'.$v.'`,';
      }
    } else {
      foreach ($field as $v) {
        $fields .= '\''.$v.'\''.',';
      }
    }
    $fields = rtrim($fields, ',');
    return $fields;
  }
  /**
   * 格式化问号
   * @param int $count 数量
   * @return string 返回格式化后的字符串
   */
  private function formatmark($count) {
    $str = '';
    if (!is_int($count)) exit($this->geterror(__function__, __line__));
    if ($count==1) return '?';
    for ($i=0; $i<$count; $i++) {
      $str .= '?,';
    }
    return rtrim($str, ',');
  }
  /**
   * 错误提示
   * @param string $fun
   * @return string
   */
  private function geterror($fun, $line) {
    return __class__ . '->' . $fun . '() line<font color="red">'. $line .'</font> error!';
  }
  /**
   * 处理表名
   * @param string $tname
   * @return string
   */
  private function formattabname($tname) {
    return '`' . trim($tname, '`') . '`';
  }
  /**
   * 析构方法
   */
  public function __destruct() {
    $this->_db = null;
  }
}